Cardiovascular disease is the leading cause of morbidity and mortality in dialysis patients and volume overload is a major contributor to its pathogenesis and progression. Central volume excess causes pressure/volume overload of the left ventricle leading to left ventricular hypertrophy, fibrosis and arrhythmias. However, excessive/rapid fluid removal and central volume depletion can also be deleterious by causing hypotension and ischemic complications such as myocardial infarction, stroke and loss of residual kidney function. Volume- related symptoms such as dyspnea, intradialytic cramping and post dialysis fatigue contribute to poor quality of life. Volume management in dialysis patients is difficult as there are no simple methods to assess central volume. The goal of this study is to determine if central volume assessment using a novel non-invasive handheld device that uses changes in blood pressure during Valsalva maneuver to assess central volume can be used for volume management in dialysis patients. We hypothesize that pulse amplitude ratio calculated by the device will be highly correlated with left ventricular filling pressures and volume-related complications in dialysis patients. We plan to test our hypotheses by: 1) measuring pulse amplitude ratio in dialysis patients scheduled for an elective cardiac catheterization; 2) measuring pulse amplitude ratio in dialysis patients in an outpatient dialysis unit, recording episodes of intradialytic hypotension and assessing quality of life; and 3) assessing the feasibility of a fluid management protocol for patients with persistently elevated pulse amplitude ratio. We anticipate that the results of this study will generate high quality data that can be used to design a volume management strategy guided by pulse amplitude ratio and we plan to test this strategy in a future randomized clinical trial. We believe that the results of these studies can potentially change the paradigm of volume management in dialysis patients providing objective data to make individualized decisions that can improve the health and quality of life of dialysis patients.